Ad groups allow for each campaign to be further subcategorized for relevance. In our hardware store example, one ad group could be for different types of rakes or varying models of leaf blowers. For the power tools campaign, one ad group might focus on power drills, while another could focus on circular saws. This level of organization might take slightly longer to set up initially, but the rewards – namely higher CTRs at lower cost – make this effort worthwhile in the long run. https://www.youtube.com/watch?v=-cQxd1gS88s&feature=kp
Search engines reward you when sites link to yours – they assume that your site must be valuable and you’ll rank higher in search results. And the higher the “rank” of the sites that link to you, the more they count in your own ranking. You want links from popular industry authorities, recognized directories, and reputable companies and organizations.
SEO techniques can be classified into two broad categories: techniques that search engine companies recommend as part of good design ("white hat"), and those techniques of which search engines do not approve ("black hat"). The search engines attempt to minimize the effect of the latter, among them spamdexing. Industry commentators have classified these methods, and the practitioners who employ them, as either white hat SEO, or black hat SEO. White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing.